This is an app that fill in on one of Apples many omissions in their own applications. iCal 2 has an automatic birthday calendar feature that syncs with AddressBook, but for some reason Apple has omitted the ability to sync custom dates, and to set alarms for the events.
DatesToiCal solves the issue nicely, and utilize OSX technology to make your calendar update automatically if you make any changes in AddressBook.
Another aspect that makes this app deserve honourable mention is the support from the developer. Initially I couldn’t make DatesToiCal work. I contacted the developer, and got a very quick response, and he was truly interested in solving the problem. As it turned out, the problem was another application to blame (the offending app hasn’t been updated for years). This commitment to customer service actually made me do my first ever contribution to donation ware.
I can only give my best recommendations.